v0.1.9.5 Naming and teaching consolidation

v0.1.9.5 consolidates the public API naming surface after the cost, sweep persistence, target-risk, and walk-forward feature arc. It adds the ledgr_candidate() extraction generic, sweep/store review helpers, refreshed teaching articles, maintainer manual traces, and scheduled hardening from the v0.1.9.4 audits. Validation-toolkit statistics, paper/live trading, OMS behavior, and default compiled execution remain future work.